1. Field of the Invention
The present invention relates to cement compositions which contain a shrinkage reducing amount of an alkyl ether derivative of an aliphatic polyhydroxy compound such as glycerin, preferably a dialkyl ether derivative and most preferably the di-t-butyl ether of glycerin.
2. Description of the Prior Art
An important disadvantage of cement mortar and concrete is the tendency to shrink and crack upon setting and drying.
U.S. Pat. No. 4,547,223 addresses this problem and suggests the use of compounds of the general formula: EQU RO(AO).sub.n H
in which R represents a C.sub.1-7 alkyl or C.sub.5-6 cycloalkyl radical, A represents one or more C.sub.2-3 alkylene radicals, and n is 1-10 as shrinkage reducing additives for cement.
U.S. Pat. No. 5,174,820 suggests reducing the dry shrinkage of cement by the addition thereto of terminal alkyletherified or terminal alkylesterified compounds of polymers having --C.sub.2 H.sub.5 O-- and/or --C.sub.3 H.sub.6 O-- as a repetitive unit.
Japan Patent Application No. 58-60293 suggests reducing dry shrinkage of cement by the addition thereto of compounds of the formula: EQU R.sub.1 OX.sub.m Y.sub.n R.sub.2
where R.sub.1 and R.sub.2 represent aliphatics, alicyclics or aromatics having 1 to 10 carbon atoms, X represents --CH.sub.2 CH.sub.2 O--, Y represents --CH(CH.sub.3)CH.sub.2 O--, m and n are 0 or greater, and m+n is 1 to 15.
Ostrikov, et al., Kolloidnyi Zhumal, Vol. 27, pp 82-86 (1965) suggests the addition of anhydrous glycerin to cement.
Despite the efforts of prior workers, the problem of shrinkage and crack formation in the drying and setting of cement compositions remains a serious problem.